Metallic vapor rectifier



y 30, 1933- A. GAUDENZI El AL METALLIC VAPOR RECTIFIER Filed Aug. 19, 1929 swa p n r 0 0 0 r mrJ 0 s H vumm n m fi Patented May 30, 1933 UNITED STATES PATENT OFFICE ARTHUR GAUDENZI AND JULIUS JONAS, OF BADEN, SWITZERLAND, ASSIGNORS TO AKTIEN'GESELLSCHAFT BROWN, BOVERI & CIE., OE BADEN, SWITZERLAND, A JOINT at;

' STOCK COMPANY OF SWITZERLAND METALLIC VAPOR RECTIFIER Application filed August 19, 1929, Serial No. 387,024, and in Germany August 24, 1928.

This invention relates to improvements in metallic vapor electric current rectifiers and, particularly to systems for igniting or starting the flow of the are through rectifiers in which the ignition is accomplished by means of a jet of the cathode material projected againstan ignition anode. I

Ifthe ignition anode ofa rectifier of the above character isconnected in a conductive relation with the metallic tank forming the operating chamber, an interruption and re newal of the cirouitwhen the direct current side is closed may cause the polarity of the jet nozzle to change in such manner that the ignition anode becomes the cathode. The entire current fromthe main anodes will then flow through the ignition anode, which has become the cathode, and through theignition voltage supplying circuit. The ignigo tion voltage supply circuitis usually constructed for voltages of only one-tenth to one-twentieth of the full rectifier voltage and any application of the full rectifiervoltage thereto will accordingly destroy the ignition system.

Several methods of .protecting a rectifier installation from reverse currents through the ignition system have been so far. developed but none have, heretofore, been found entirely satisfactory. The possibility of destruction of the ignition system by the set of circumstances above set forth may, of course, be avoided by insulating the ignition anode from the rectifying chamber but such construction is both expensive and unsatisfactory, due chiefly to the difliculty of sealing such insulating structures in a vacuum tight manner. The application of zero voltage protective devices or systems likewise complicates the rectifying installation very greatly and materially increases the cost thereof.

It is, therefore, among the objects of the present invention to provide a jet ignition system for electric current rectifying installations of the metallic vapor type in which the ignition anode need not be insulated from the rectifier casing to secure safe operation thereof.

Another object of the invention is to provide means which will prevent the flow of the full rectifier voltage through the ignition sup ply system of the installation in case of abnormal operation thereof. 7

Another object of the invention is to provide means in the ignition supply circuit of a metallic vapor rectifier which will permit the flow of current therethrough in only one direction.

A further object of the invention is to provide an ignition system for rectifier installa- '6? .tions in which an electric valvev in the ignitionsystem is connected with the direct current or output side of the rectifier.

Objects and advantages, other than those above set forth, will he apparentfrom the fol.- F lowing vdescription and the drawing inwhich;

Figure '1 shows a diagrammatic embodiment of the present invention, and

I Fig. 2 shows a modification of the .embodi ment illustrated in Fig. 1. V

Referring more particularly to the drawing by characters of reference, the reference numeral 5 indicates supply lines connected with the primary winding 6 of a'main supply transformer. The secondary winding 7 of the main supply transformer'is connected with the anodes'8 arranged within a rectifying chamber of a metallic tank'9, of any suitable construction. The rectifier is provided with a depression'or well 25insulatingly connected with one portion of the tank 9 to receive cathode material ;11 which is pref- V erably a'metallicfiuid such as mercury. The midpoint of the transformer secondary? and the cathode 11 are connected to forma circuit through a direct current consumingdevice or devices12.

The ignition anode 13, connected in con ductive relation with the rectifier tank 9, extends into proximity with the cathode 11 in suchmanner that a jet of the cathode material maybe projected thereagainst by suitable means. Theignition anode is-connected with one end of the secondary winding 16 of a transformer and the other end of the sec- 295 ondary winding 16 is connected through an electric valve 17 which, in the embodiment illustrated in Fig. 1 and described immediately above, is preferably of the oxide; coated plate type, with thedirect current line from '100 the cathode 11 to the direct current consuming device 12. The transformer secondary winding 16 is supplied from a supply line 18 by means of a transformer primary winding 19.

In the embodiment shown in Fig. 2, the electric valve 17 instead of being of the oxide coated plate type is replaced by an electric valve of the hot cathode type. The cathode 22 of the hot cathode electric valve is connected through the transformer secondary winding 16, and may be disconnected from the ignition anode by means of a switch 21. The cathode 22 of the hot cathode valve is connected with a tertiary winding 23 arranged in inductive relation with the secondary Winding 16 of the transformeigboth the secondary winding 16 and the tertiary winding 23 being supplied by the primary winding 19. The operative connection of the tertiary winding 23 with the hot cathodej22 includes a switch 24, and the anode 20 is connected with the directcurrent line leading from the cathode 11 to the direct current consuming-device 12.

If the rectifying installation is in operation,that is, if the current flows from the transformer secondary 7 through the anodes 8 to the cathode 11 and-to the directcurrent consuming device 12, and the voltage of the supply lines 5 fails, the are is momentarily quenched and the jet ignition system again operates. If the ignition anode 13 were being supplied, at the moment of the renewed operation of the jet ignition, by the negative half wave from the transformer 16, 19, the ignition anode would be negative with respect to the cathode 11. It'is, however, impossible for the negative half'wave to flowthrough the ignition anode 13,because the path of the current is blocked in the direction by the valve 17.

v The igniting operation accordingly may take place only when the ignition anode 13 isexcited by'the positive half wave of the current supplied by the transformer 16. v.19 and it is impossible for the current to flow through the ignition anode, because at the time of the'ignition, the anode will be positive with'respect to the cathode. The occurrence of a negative or cathode spot, even momentarily, on the ignition anode is accordingly avoided.

Instead of utilizing an electric valve in the circuit, a'reverse current relay or any other similar device operating inthe ignition circuit upon the occurrence of a reverse current therein, may also be utilized. It will be apparent that prevention of the reversal of the 'flow of current through the ignition system completely protects the ignition anode againstbecoming negative with respect to the cathode and, therefore, forming an electrode to which the are from the anodes may become attached. The disturbances incident to such abnormal operation in a rectifier installation are accordingly prevented. All of the complicated reverse current protective systems and devices and the insulating constructions between the ignition anode and the rectifier tank are eliminated together with the inherent possibilities of failure and the expense of construction thereof.

Although only two embodiments of the present" invention have been illustrated and described, it will be understood that various other embodiments are possible, and that various claims may be made Without departing from the spirit of the invention or the scope of the claims.

The invention claimed is:

1. In a system for igniting an electric current rectifier of themetallic vapor type, a metallic casing forming an operating chain ber, an anode and a cathode within and insulated from said casing, an ignition electrode connected in conductive relation with said casing and extending into the operating chamber of the rectifier, a supply circuit connected'with said electrode, and an electric valve forming a portion'of said supply circuit to permit the flow of current there- 'throughbetween'said electrode and cathode in only a single direction." r g 2. In a current rectifying system, a current rectifying apparatus comprising a metallic container, an anode and a cathode Within and insulated from said contain er,'an'ignition'electrode connected in conductive relation with and extending into said container, a supply circuit connected with said electrode,

and an electric valve forming a portion of said supplycircuit to permit flow of current between said electrode and said cathodeand to prevent flow of current between said anode and said cathode by way of said electrode.

"1. 3. In a current rectifying system, a current rectifying apparatus comprising a metallic container, an anode and acathode' within and insulated from said container, a current supply circuit connected with said anode therebetween, an ignition electrode connected in conductive relation with and extending into said container,.a supply circuit connected with said electrode and said cathode,

and said cathode to permit flow of current and an electric valve forming a portion of last said supply circuit topermit flow of current between said electrode and said cathode and to prevent flow of current between said anode and said cathode by way'of said container. 7

' 4. In a current rectifying system, a current rectifying apparatus comprising a metallic container, a cathode and a plurality of anodes within and each insulated from said container, a source of current supply connected with said cathode and said anodes to permit flow of current from said anodes to said cathode, an ignition electrode connected in conductive relation with and extending into said container, a current supply "K circuit connected With said electrode and said cathode, and an electric Valve forming a portion of last said supply circuit to permit flow of current between said electrode and said cathode and to prevent flow of current from said anodes to said container.

In testimony whereof We have hereunto subscribed our names this 6th day of August ARTHUR GAUDENZI. JULIUS JONAS. 

